1. Field of the Invention
This invention pertains to concrete and steel construction, and is directed particularly to composite open-web steel joist and wire mesh reinforced concrete slab construction to provide a more rigid and more economical composite floor or roof structure in building construction as compared to prior art construction.
2. Background of the Invention
The improvement in this application pertains specifically to an improvement in the composite concrete slab and steel joist construction disclosed in U.S. Pat. No. 3,728,835, of the same inventor. It also relates to other patents covering elements of a composite beam and joist floor system including U.S. Pat. Nos. 3,392,499; 3,457,818; 3,527,007; 3,624,980; 3,683,580 and copending application Ser. No. 491,696.
Specifically the system disclosed in these prior patents provided for composite action between a poured-in-place concrete slab and open-web steel joists utilizing apertured sheet metal formwork members in association with open-web steel joists, the upper apex portion of the zig-zag webbing of which projected through the upper joist chords so as to project through the formwork openings and act as sheer members in the hardened concrete slab thereafter poured. This system included wedge means for interlocking the protruding apex shear portions of the joist webbing with respect to the sheet metal formwork, thereby eliminating the need for welding such sheet metal formwork to the joist chords.
The present invention represents an improvement over the prior art system, particularly as disclosed U.S. Pat. No. 3,782,835, in that it provides for a continuous round rod being secured to the apex of each joist web projection longitudinally along each joist. Under some design conditions this rod will perform all or most of the functions performed by the wedge means in the prior patent. Additionally the rod serves as a support means for draping a wire reinforcing mesh between joists for reinforcement of the concrete slab. By draping the mesh from rod to rod, the mesh will be near the top of the concrete slab over the joists and near the bottom of the slab midway between joists. The draping use of the wire mesh greatly adds to the strength of the concrete slab and enables joists to be spaced further apart. Both improvements result in lower material and erection costs.